1. Field of the Invention
The present invention relates to vehicle trailers for carrying boats, and more particularly to an improved boat trailer that permits safe one-man launching and recovery in uneven ramps or beaches.
2. Description of the Prior Art
Conventional prior art boat trailers are generally adequate for launching and recovering boats when a properly designed and maintained launching ramp is available, and when the water is relatively calm. However, when launching from a sand beach or the like, the trailer may tilt laterally. When the trailer includes outrigged guidearms, an arm on one side may be low or below the water level. In such case, there will be a risk of damage to the boat hull. When recovering a boat in windy weather and rough water, there is a risk of damage when the bolster or cradle elements are well below the surface of the water. This situation is also aggravated when the bottom surface of the body of water is uneven and the trailer tilts laterally. To safely launch and recover a boat, prior art trailers generally require two persons if possible damage to the boat is to be avoided.
Attempts to solve some of the above problems are known. In U.S. Pat. No. 3,608,754 to Park, a pair of bolsters at the rear of a trailer chassis is attached to a pair of long arms pivoted near the front of the chassis. A large flotation block is mounted below the bolsters. When the trailer is backed down a ramp, the pair of bolsters tend to float. Although this construction is an improvement over the conventional trailer, it does not solve the problem of uneven surfaces since one bolster may be above the water level and the other bolster below water. MacKusick et al., U.S. Pat. No. 3,122,245, disclose a trailer with longitudinally pivoted cradle pads which tend to fit the hull shape but which will normally be under water. Wood, U.S. Pat. No. 4,529,217, teaches a set of outrigger arms with automatic alignment means. Pat. Nos. 4,530,634 and 4,592,694 to Johnson both disclose horizontally pivoted rollers which pivot to match the hull contour of a boat. None of these patents fully solve the problems of one-man launching and recovering a boat in rough water and on an uneven ramping surface.